Merge pull request #255 from skylot/xml_unreadable_chars_escapes

Adds more escape for unreadable characters so parser won't throw exceptions during parse

jadx-core/src/main/java/jadx/core/utils/StringUtils.java

@@ -149,6 +149,9 @@ public class StringUtils {
 	}
 
 	private static String escapeXmlChar(char c) {
+		if(c >= 0 && c <= 0x1F) {
+			return "\\" + (int) c;
+		}
 		switch (c) {
 			case '&':
 				return "&amp;";
@@ -160,6 +163,8 @@ public class StringUtils {
 				return "&quot;";
 			case '\'':
 				return "&apos;";
+			case '\\':
+				return "\\\\";
 			default:
 				return null;
 		}